Symantec Endpoint Protection Firewall and Firefox Hello

Hi,

since I upated Firefox with the new one Hello version I receive advice from the Firewall that the traffic has been blocked Firefox.exe by rule block UPnP discovery on port 1900. it happens several times (every around 3 minutes) during using Firefox but I never use or open the "Hello feature" of Firefox.

Is it normal?

It happens just to me ?

it could be a seriuos alarm ?

If  is tt safe how to add an exception ?

Is like something Skype that  tries to open udp port on router ?

SEP Small Business Edition 12.1.4100.4120

Thanks